The present invention relates to a process for molding a make-up composition by casting in a mold, in fluid form, and solidifying the composition, so as to obtain a solid molded product in the form of a block or cake, it being subsequently possible for the composition to be picked off from the molded product with the aid of a finger, a brush or of a puff; the invention also relates to the product obtained by this process.
The make-up composition to be molded may be in the form of a paste obtained by mixing a solid particulate phase either with an aqueous phase or with a binding agent, especially a fatty phase, in a solvent; it may also be in the form of a product based on a heat-fusible wax or of a gel which is cast in the hot state. Depending on the composition employed, the solidification therefore takes place either by evaporation of water or of solvent, or by cooling, or by chemical reaction.
It is known to cast a make-up composition in a mold of a certain volume including chiefly a molding surface which imparts its shape (flat, curved or provided with relief or indented figures) to the surface for taking off the composition and a bottom, in most cases flat, provided with one or more openings through which the composition to be molded is cast. Depending on the make-up composition which is processed, the phenomenon of shrinkage during the solidification may be considerable. This is the case especially with the compositions described in patents U.S. Pat. No. 4,804,538, EP-A-165,137 and DE-A-3,327,001. The molded block obtained is then packaged but, because of the shrinkage, its dimensions and its shape can vary, and it is difficult to keep it in place in this package and to wedge it against the rigid surface forming the bottom of the package such as a case; the main function of the rigid surface is to prevent the molded block from breaking up in the course of the various handling operations and to protect it, but the shrinkage destroys the wedging and prevents the packaging from fulfilling its function in a satisfactory manner. If the molded block is badly wedged it tends to break up in the course of storage; because of its nature it is actually very brittle because it must be capable of being disintegrated to allow it to be picked off.
To avoid this disadvantage it has already been proposed, in EP-A-191,198 and in EP-A-38,645, to perform the casting in a dish resting on a molding surface, the bottom of the dish being provided with crosspieces, reinforcement or other anchoring devices. On solidifying, the composition binds to the bottom of the dish and a product of molding is then packaged, including the solidified composition and its associated dish. The dish is used as a support for the solidified composition and, since the dish has determined dimensions, the molded product is easy to keep in place and to wedge in a rigid package. However, it has been found that after drying or cooling, cracks are formed because of shrinkage of the composition in relation to the dish and to the regions for bonding to the latter. The product sold is consequently embrittled and tends to fragment during the various subsequent handling operations, especially when the product is being used.
It is therefore desirable to define a packaging for this type of composition, which at the same time makes it possible to ensure the wedging and the maintaining of the solidified composition in a protective packaging eliminating the risk of breaking up and to permit the shrinking of the composition without embrittlement of the molded block; two functions must therefore be ensured simultaneously.
According to the present invention it has been found that the abovementioned disadvantages are avoided by employing a mold bottom including a sheet of open-cell foam which is partly impregnated with the cast composition. The process according to the invention makes it possible to ensure the two desirable functions defined above simultaneously with the product obtained.
The subject of the present invention is therefore a process for molding a make-up composition in a mold including a concave molding surface forming the base of the mold and a bottom forming an upper component of the mold and shutting off the space bounded by the said molding surface, the composition being cast in the mold in fluid form and subsequently solidifying to form a demoldable solid product capable of being packaged, characterized in that the said composition is cast in a mold the bottom of which is at least partly formed by a sheet of open-cell plastic foam, so as partly to impregnate the foam sheet with the composition. After solidification of the composition a molded product, including the solidified composition and the foam sheet which is bonded to it and which forms its support, is demolded by removing the molding surface.
It has been found that, in the process according to the invention, compositions exhibiting a high shrinkage during their solidification can be cast without the molded product obtained being fragile because the foam support adapts its shape to the dimensional changes in the solidified composition by virtue of its elasticity. Nevertheless, since the foam is partly impregnated with the composition, a bond is formed between the plastic foam sheet and the composition during the solidification and the said foam sheet forms a support for the solidified composition, a support which, of itself, contributes to the mechanical reinforcement of the molded block. A molded product is therefore prepared, including the combination of the solidified composition and the foam sheet. The unimpregnated portion of the foam sheet, more particularly the unimpregnated layer of the foam sheet, which has retained its elasticity, can be employed in the packaging of the molded product to wedge the latter onto a rigid surface by compensating the changes in dimensions of the solidified composition; the wedging is produced by a slight compression of the foam sheet. In addition, the solidified composition, being held in the package on an elastic surface, is properly protected against the impacts to which it might be subjected during the various handling operations. A good conservation of the molded product is therefore ensured as soon as it is manufactured, until it reaches the user""s hands.
According to a first embodiment the composition is solidified after casting by cooling or by evaporation of a solvent present in the composition. According to another embodiment a composition which contains plaster (CaSO4.xc2xdH2O) and a sufficient quantity of water to obtain a pourable mixture is cast, the solidification taking place after casting by setting of the plaster. The molding process according to the invention is then particularly advantageous.
According to the invention the composition may be cast through the foam sheet; casting takes place preferably through an opening, advantageously a central opening, made in the foam sheet. The size of this opening is a function of the size of the mold and of the composition which is cast.
The foam sheet is preferably slightly compressed at the solidification stage, advantageously with the aid of a rigid plate; this rigid plate is advantageously provided with openings to facilitate the evaporation when the solidification takes place by evaporation.
The foam sheet employed according to the invention includes, as indicated above, an open-cell plastic foam. This foam is chosen so that it practically does not swell in the presence of the various ingredients of the make-up composition, such as water, oil and fatty substances, and so that it can be impregnated with the composition. A foam is advantageously employed which has a cell structure such that the volume occupied by the walls of the cells does not represent more than 3% of the total volume of the foam. The foam advantageously has a homogeneous cell structure, that is to say forming a three-dimensional network. Suitable plastic foams are, for example, crosslinked polyurethane foams, in particular those marketed under the names xe2x80x9cBulpren S 20xe2x80x9d, xe2x80x9cBulpren S 30xe2x80x9d and xe2x80x9cFiltren S 2120xe2x80x9d by the xe2x80x9cRecticelxe2x80x9d company.
The thickness of the foam sheet employed is a function of the size of the mold and of the composition which is cast. A suitable thickness is generally of the order of 3 to 6 mm.
Another subject of the present invention is the molded make-up product obtained by the process defined above.
This product is preferably packaged, after demolding, in a rigid display case including a component which supports the foam sheet and of a ring which surrounds the molded product and is integrally attached to the component.
In a first alternative form the component is a base which interacts with a ring which bears on the solidified composition to hold the molded product against the base, the base overlapping laterally in relation to the foam sheet.
In a second alternative form the component is a plate and the ring includes a means of integral fastening capable of ensuring peripherally, in a removable manner, its bonding to a cap in order to form a molding surface with it. In addition, the plate preferably includes at least one opening.
Provision can be advantageously made for the product according to the invention to contain hydrated plaster (CaSO4.2H2O), preferably in a proportion by weight of between 10 and 50%.